which element is found in both dna and protein?\nsulfur\nsodium\nnitrogen\nchlorine

Answer:

C. nitrogen

Explanation:

Step1: Analyze elements in DNA

DNA (deoxyribonucleic acid) is composed of carbon ($C$), hydrogen ($H$), oxygen ($O$), nitrogen ($N$), and phosphorus ($P$).

Step2: Analyze elements in protein

Proteins are made up of carbon ($C$), hydrogen ($H$), oxygen ($O$), nitrogen ($N$), and sometimes sulfur ($S$).

Step3: Find the common element

By comparing the elements of DNA and protein, we can see that nitrogen ($N$) is present in both. Sulfur is only in some proteins, sodium and chlorine are not in DNA or proteins in significant amounts in this context.